Phase noise and polarization crosstalk resulted from the cross-phase modulation are one of the main sources leading to the cost of a dense wavelength division multiplexing system. Traditional methods for researching the XPM comprise Split Step Fourier (SSF) simulation and a transmission experiment. However, the SSF simulation is very time-consuming and the number of time windows and channels which can be studied is very limited; and the transmission experiment needs to spend a lot of manpower and material resources. In order to research the mechanism of the cross-phase modulation better so as to suppress and compensate impairments of related signal, various methods have been proposed successively (referring to documents Z. Tao et al., JLT, vol. 29, pp. 974-986, 2011; M. Winter et al., JLT, vol. 27, pp. 3739-3751, 2009). However, polarization mode dispersion is not taken into consideration in these methods, while the polarization mode dispersion does exist in a practical fiber transmission system. Moreover, the researches (referring to documents P. Serena et al, ECOC, Paper 10.4.3, 2009; C. Xia et al, ECOC, Paper Th. 10. E, 5, 2010) have shown that the polarization mode dispersion is conducive to reduction of the system impairments due to the cross-phase modulation in a fiber link including dispersion management. Therefore, when the impairments of related signal are suppressed and compensated, it is needed to consider the effects brought by the polarization mode dispersion.
It should be noted that the above introduction to the background art is given for the clear and complete description of the technical solution of the present invention and for the understanding by those skilled in the art. The above technical solutions should not be deemed as being known to those skilled in the art for having been described in the background art of the present invention.